Chaelbs p



(No Model.)

0. P. GROUT.

ARTIFICIAL TOOTH.

No. 330,831. Patented Nov. 17, 1885.

N. PETERS Phnln-Lilhographer. Washinglnn. 17.:

UNTTnn STATES PATENT Trice.

CHARLES P. GROUT, OF NEW YORK, N. Y.

ARTIFICIAL TOOTH.

sE -crrrcartom forming part of Letters Patent No. 330,831, datedlh'ovember 17, 1885.

Application filed July 9, 1885. Serial No. 171,042. (No model.)

To all whom it may concern:

Be it known that I, CHARLES P. GROUT, of the city and county of NewYork, in theState of New York, have invented a certain new and usefulImprovement in Artificial Dentistry, of which the following is aspecification.

My invention relates to artificial tooth crowns which are provided witha band portion which receives and is fitted snugly upon apreviously-prepared tooth root or stump, and forms the occluding surfacefor the opposite teeth to bite against. Very frequently it is necessarythat these crowns should have porcelain faces aflixed to them, so as tosimulate the appearance of natural teeth; and it is necessary,too,inthis way to crown teeth which would not otherwise have to be crowned inorder that the crowns may support one end of a metal bridge whichextends over a space from which teeth have been lost by decay.

When a porcelain-faced crown is to'be applied to a tooth the nerve ofwhich is alive and healthy, it is often necessary to cut away aconsiderable portion of the tooth structure in order to accommodate theporcelain face of the crown, which is usually of considerable thickness;and the object of my invention is to so construct porcelain-faced crownswhich are to be applied to healthy teeth that it will be necessary tocut away very little of the tooth structure.

In carrying out my invention I grind a porcelain face or tooth toconcave form upon the inner side, so that it will conform to the convexcurvature of the band portion of the cap or crown, and the porcelainface has in its inner surface two pins, or a number of small pins, towhich a metal backing may be secured. If a small drop of gold be placedon each of these pins, and the metal backing be laid thereon and thensubjected to heat, the gold or gold solder will effect a firm union ofthe metal back with the pins, and a porcelain face thus backed may besoldered to the cap or crown. These pins need not project beyond theconcave inner surface of the porcelain face, and when the course abovedescribed is observed the metal backing will be found to be firmly fixedto the porcelain face.

The advantage of a number of small pins is that they will yield toaccommodate shrinkage in sweating the metal backing to the porcelainface,and in securing the backed porcelain face to the metal crown, andthe porcelain face will not be so liable to split as it would be iflarger pins were used.

In the accompanying drawings, Figure l is a sectional elevation of atooth with a metal crown applied thereto and having a porcelain faceembodying my invention, and showing also the alveolar process orjaw-bone and the gum-tissue. Fig. 2 is a horizontal section ofa crownand its porcelain face, and Fig. 3 is a view of the inner side of theporcelain face before the metal backing is applied thereto.

Similar letters of reference designate corresponding parts in theseveral figures.

A designates the tooth; B, the metal crown which is applied thereto.

0 designates the alveolar process or jawbone, and D designates thegum-tissue, which projects above the alveolar border, here representedby the dotted line a.

The artificial crown B, which is closed at the top, may be of theordinary construction, and composed of a simple continuous band portionfitting the exterior of the tooth; or it may have a longitudinal splitor division, and a clamp, (1, applied thereto, securing the abuttingedges of the band portion, as is described in my application for LettersPatent, Serial No. 164,401, filed May 4, 1885. The purpose of thussplitting or dividing the band is fully described in my aforesaidapplication, and such divided band and its key or clamp forms no part ofmy present invention.

B designates the porcelain face of a tooth, which is as thin as isconsistent with the necessary strength, and is ground concave upon itsinner side, so as to fit the convex curvature of the band portion B, aswill be readily understood from Fig. 2. This porcelain face B has anumber of small pins, projecting from or presented at its inner surface.These pins may project very slightly beyond the inner surface of theorcelain face, or they may be ground off flush therewith.

The porcelain face B has upon its inner surface a metal backing, b,which may be of gold or plat-ina, or a bimetallic plate of gold andplatina, or of any other suitable metal. This backing b is burnisheddown so as to fit the concave curvature of the inner surface of theporcelain face, and is also burnished over the edges of the porcelainface, so as to cover them and make a neat finish, as shown in Fig. 1.

Vhen the metal backing is to be fixed to the porcelain face, a smalldrop of gold is to be placed upon each of the pins and heat beingapplied after the metal backing is placed upon the porcelain face, thebacking will be firmly united to the pins by the gold or gold solder,and the metal-backed porcelain face may then be soldered or sweated tothe metal crown.

It will be seen that by grinding the inner surface of the porcelain faceto a concave form, so that it will conform to the convex curvature ofthe band portion of the crown, I am enabled to obtain a porcelain-facedcrown which will conform outwardly to the appearance of the naturalteeth without cutting away any great portion of the tooth which is thuscrowned, and hence without the pain to the patient incident thereto, andwithout weakening the tooth and incurring the possibility of disease orinflammation therein.

I do not limit my invention to porcelain faces having a number of smallpins secured in them, as the porcelain teeth now in the market, andhaving two larger pins, may be ground down on their inner surface, so asto 30 give them proper form, and then employed in carrying out myinvention. It is desirable, however, to employ porcelain faces having anumber of small pins, because the small pins will yield more readily toshrinkage resulting from soldering the backing to the porcelain face andthe backed porcelain face to the crown, and will not be liable to splitthe porcelain face.

I do not claim, broadly, as of my invention a metal tooth, including itsmasticating surface, combined with a thin porcelain facing.

What I claim as my invention,and desire to secure by Letters Patent, is

1. The combination, with a metallic toothcrown, of a porcelain face theinner side of which is concaved to fit the crown, and which is providedwith two or more metal pins and a metal backing for the concaved side ofthe porcelain face, sweated to said pins and sweated or soldered to theexterior of the tooth-crown, substantially as herein described.

2. As a new article of manufacture, a porcelain tooth or tooth-facehaving its back concave and provided with metallic pins presented at theconcave back, substantially as herein described.

CHAS. P. GROUT.

Witnesses C. HALL, FREDK. HAYNES.

